In this Specialized Center of Research on Pediatric Pulmonary Disease, several clinical and basic research projects are being used to explore the pathogenesis of cystic fibrosis, to develop better tests for the cystic fibrosis gene and to examine certain aspects of host defense mechanisms in cystic fibrosis. Projects include studies of an invertebrate sea animal model of mucus-producing cells which respond to cystic fibrosis body fluids; isolation, purification and characterization of cystic fibrosis mucus-producing factors; a study of several serum proteins in cystic fibrosis; polyamine metabolism in cystic fibrosis; and host defense measurements in cystic fibrosis, including adherence of bacteria to buccal mucosal cells and lysozyme levels. A Clinical Core, a Laboratory Core, and an Administrative Core serve to integrate the other five projects.